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M. GRUBER. v AHRANGEMENI FOR COOLING HIGH SPEED DYNAM'O ELECTRIC MACHINES.

' APPLICATION FILED MAY 26. 1919.

1 ,3 1 6,790. Patented Sept. 2:5, 1919.

f mixeauniia-,-orcmva, swimwear?- aaaancmamrr roa'cooLme iIcR-srnnn ammo-meme MACHINES.

- Specification a; Patent. Patented '23, 1919- Application filed Kai- 2 s, 1919.1 Serial iw Laaaesa.

' To all whom it may concern;

Be it known that I, Mex GRUBER, a citiiien of the Swiss Republic, and residentof Ge neva, Switzerland, have invented a new and useful Arrangement forCoolin'g High-Speed Dynamo-Electric Machines, of which-the following a full, clear,la'nd exact speci'fication. v f v A large number of different. arrangements for cooling high speed dynamo-electric machines are known, in which the rotor of the machine, with or without theaidfofa spe-' cial ventilating device drives cooling air through the chambers and passages provided for cooling.-- According to whether the Ven:

jt-ila'ting device is located at the inlet, outlet or in the middle of theair' pass'age, a'pressure action, a suction action or a-combined pressure and suction action results. If .the

active iron elements ,of the machine. are sub-x divided in an axi al=direction by meansfof so called air gaps,-w'hich essentially form radially directed coolingrsurfaces, the action is terme'dradial cooling: on the other hand, if the iron is traversed by cooling passages which; run parallel to the axis, the action is termed axial cooling. The supply 'ofair r to the radial air gaps must obviously be effected through axial passages, whereasthe axial longitudinal passages. may also'vcom municate with radially arranged air outlet I ports.-

The "subject matter of the present iniention is a cooling arrangement in accordance with the'last mentioned'system The novel feature thereof consist-s in'that the cooling'air for the'stat'or is mainly sucked up and driven of the rotor. "This can be "effected by an' by the ejector action of the air passing out arrangement in which the cooling air is supplied ,to the rotor and'thefstator of the inachine separately from both sides being {transmitted through longitudinal passages and, at themiddle of the laminated core conveyed away in a radial direction. For

this purpose the active iron in the rotor and stator is subdivided 'ii o two sections beascertained the nature of my saidinvention tween. which the ventilating passage is located. A special ventilating device is; un-.

necessary if the requisite suction action, is already effected by means of the'free portion of the winding at this point. The rotoris provided with-axial passages and the air j flows through the suction ventilator thus constitutedzind passes out through the radial slot. This air causes an ejector action throng and first sucks cooling, air through the annular air gap between the rotor and stator and then through the axial'sta'torpassa s sucks'up further coolin air, which is a o driveneradially outwa This method of 'cooling has the advantage that the heating of the cooling air. reduced by the compress on and losses in t e suction" ventilator, only occurwvhen-- the air has. alreadyeffected its cooling action and'is leaving the machine,

whereas with the pressure coolin system generally employed, the airis heate by com pression before exercising itsc'ooli i f-unc-l tionywhereby the latter is substantia ly impaired;v If it is desired to increase the r amoiint' of air supplied to the stator above that due -to the ejector action, then at the sides of the rotor special fan blades may be arranged which supply an additional amount of freshair to the stator. This is shown in the'left half-of the constructional example shown in ion tudinal.

section in the annexed drawing, w ereas at the righthand end of the machine the fan blades are omitted. The rotor 1" andthe stator s consist. of two laminated core sections between which. a space m, n is left'free for conveying, away. the heated cooling air in the passages 70, Z The fresh air flows in portionthereofin sucked up by the ventipartly from the interior of-the end-bells or caps'p through the longitudinal passages-l the side ports e of the'easing g'; a

of the stator to the middle space 1L and from thence to the outletport a in the stator casguide membersb are provided at the endsof the stator passages -Z,- .In order to obtain an effective ejector action also in the air gap (1,

the'radial'slot' m in the rotor is narrower in an axial directionahan theslot 11 in the stator.

Having now particularly described and pa'ssages in an axial direction through their 'magnetic cores, of an ejector device -for ingg. n order to .increase"the.-e ector action g of air in the rotor, the air from the rotor inducing the flow of air through the'stator.

I sucking coolin the stator, ancF means for producing a flow 2. In an arran eme'nt for coolingi-ahigh speed electric mac ine, the combination w th a stator and a rotor formed with passages in aniaxial direction through their magnetic cores, of an e ector device for sucking cooling air through the. passages of the stator,

the active. iron of said rotor-and of said stator divided into two sections and forming a radiallyextending air assage between said sections, means ,for pro ucinga flow of air in the rotor portion of said air passage,

said means adapted to induce a flow" of air through the stator portion of the air passage.

3. In an arrangement for coolinga high speed electric machine, the combination with a stator and-a rotor formed with passages'in an axial direction through their magnetic cores, of an ejector device in the stator, the active iron of said rotor and of said stator divided into two sections and forming a radially extending air passage between said sections, means for producing a flow of air in the rotor portion of'said radial passage, said air flow causln an ejector action in the stator portion 0 said passage, in which said ejector device is located, said ejector device comprisln guide members adapted to effect a "werfu e ector action on the cooling air '0 the stator.

- 4. In an arrangement for cooling'a high speed electric machine, the comliinationwith air through the passages in,

a stator and rotor formed with passages in an axial direction through their magnetic cores, of an ejector device, the active iron of said rotor and of said stator divided into .two sections and forming a radially extend. ing air assage between said sections, means for pro ucing a flow of air in the rotor portion-of saidradi'al passage, said air flow causing an ejector action in the stator portion of the passage, the-radial air passage in the rotor being of smaller cross-sectional area than in the stator, whereby the ejector action is made more powerful.

5. In an arrangement for cooling :1 high speed electricmachine, the con'lbination with a stator and a rotor formed with passages in an axial direction through their magnetic cores, of an ejector device, the active iron of said rotor and-ofsaid stator divided into two sections and forming a radially extending air passage between'said sections, a veil tilator in the radialpassage of the rotor for producing a'fiow of air through said radial passage, said air flow-causing an ejector action in the stator portionof said radial pas- 

